Resistor with a secured mounting strap



- Juh e 25, 1968; J. 'R. OKEEFFE 3,390,367

' I I RESISTOR WITH A SECURED MOUNTING STRAP Filed March 16, 1966 INVENTOR. (124/55 1?. 0%:2-772' xrrole/ve'rs United States Patent ()flice 3,390,367 Patented June 25, 1968 3,390,367 RESISTOR WITH A SECURED MOUNTING STRAP James.R. OKeeffc, Columbus, Nebn, assignor to Dale Electronics, Inc., Columbus, Nehru, a corporation of Nebraska Filed Mar. 16, 1966, Ser. No. 534,862 14 Claims. (Cl. 338-418) ABSTRACT OF THE DISCLOSURE A mounting means for securing a mounting strap to a resistor having a body portion with a bore extending therethrough which is adapted to slidably receive the mounting strap. The mountingmeans is positioned on the mounting strap adjacent each of its ends and is movable into engagement with the end of the body portion adjacent thereto to provide vibration resistance qualities to the assembly.

Certain of the resistors now being produced are provided with an elongated, substantially rectangular bore extending through the resistor body. These resistors are usually secured to a mounting panel or the like by means of a substantially flat rectangular mounting strap extending through the bore in the resistor body, the mounting strap being secured to the mounting panel or the like in a spaced relationship thereto to aid in the dissipation of heat therefrom. The securing of these mounting straps to the resistor is a problem troublesome to the manufacturers of the resistors. Several different methods have been attempted in an effort to rigidly secure the strap to the resistor, all of which are unsatisfactory. One method used heretofore was to provide tabs punched in the mounting strap which are designed to engage the resistor body within its bore. The disadvantages of the punched tab method are: (l) The tabs do not hold well under severe vibration and in some instances must be cemented to the resistor; and (2) the mountin straps must be thin in order to allow room for the tabs and as a result of the thinnness thereof, provide poor heat dissipation thereby lowering the Wattage rating of the resistor.

Another method used heretofore Was to cement the mounting strap to the resistor. The necessity of the cement operation requires a secondary operation for application and cure which results in the resistor being more expensive of manufacture. Additionally, the cement frequently cracks during thermal cycling thereby causing vibration failures.

Therefore, it is a principal object of this invention to provide a means for securing a mounting strap to a resistor which provides excellent vibration resistance qualities to the assembly.

A further object of this invention is to provide a means for securing a mounting strap to a resistor which eliminates vibration resistance problems in the resistor art.

A further object of this invention is to provide a means for securing a mounting strap to a resistor which prevents any movement of the resistor with respect to the mounting strap.

A further object of this invention is to provide a means for securing a mounting strap to a resistor which includes an eccentric or cam means which is movable into engagement with the resistor.

A further object of this invention is to provide a means for securing a mounting strap to a resistor which permits sufficient heat transfer through the mounting strap.

A further object of this invention is to provide a means for securing a mounting strap to a resistor which permits the resistors to be stacked Without interference between the stacked resistors.

A further object of this invention is to provide a means for securing a mounting strap to a resistor which is economical of manufacture, durable in use and refined in appearance.

These and other objects will be apparent to those skilled in the art.

This invention consists in the construction, arrangements, and combination of the various parts of the device, whereby the objects contemplated are attained as hereinafter more fully set forth, specifically pointed out in the claims, and illustrated in the accompanying drawings in which:

FIG. 1 is a side elevational view of one means of securing a mounting strap to a resistor, the movement of the spacer elements being illustrated by broken lines;

FIG. 2 is an end elevational view of the means of FIG. 1;

FIG. 3 is a side elevational view of the spacer element of FIGS. 1 and 2;

FIG. 4 is a top elevational view of the spacer element of FIG. 3;

FIG. 5 is a further elevational view of the spacer element of FIG. 3;

FIG. 6 is a fragmentary side elevational view of a second means of securing a mounting strap to a resistor;

FIG. 7 is a fragmentary top elevational view of the mean."- of FIG. 6;

FIG. 8 is a fragmentary side elevational view of a third means of securing a mounting strap to a resistor;

FIG. 9 is a fragmentary top view of the means of FIG. 8 with portions thereof cut away to more fully illustrate the invention;

FIG. 10 is a fragmentary side elevational view of the fourth. means of securing a mounting strap to a resistor;

FIG. 11 is a fragmentary top view of the means of FIG. 10 with portions thereof cut away to more fully illustrate the invention; and

FIG. 12 is a fragmentary top view illustrating two resistors in a stacked position.

The numeral 10 generally designates a resistor (FIGS. 1 and 2) of conventional design which is provided with a substantially rectangular bore 11 extending through the resistor body 12 which is adapted to slidably receive a flat, substantially rectangular mounting strap 13 extending therethrough. Mounting strap 13 is provided With openings 15 and 17 formed therein at opposite ends thereof. As stated before, resistor 10 is of conventional design and includes terminals 19 and 21 operatively secured thereto adjacent opposite ends thereof. Terminals 19 and 21 are in operative connection With a resistance wire (not shown) in resistor body 12. Resistor 10 and its bore 11 are coated with a suitable coating 23 in conventional fashion.

The numeral 25 generally designates a spacer element consisting of a cylindrical portion 27, a shoulder portion 29 and a cylindrical portion 31. Spacer element 25 is provided with a bore 63 extending t-h'erethrough as best illustrated in FIG. 4. The axis of bore 33 coincides with the axis of cylindrical portion 31 but is offset from the axis of shoulder portion 29 and the axis of cylindrical portion 27 as also best illustrated in FIG. 4.

Cylindrical portion 31 is adapted to be received by either of openings 15 and 17 in mounting strap 13 as illustrated in FIG. 2. As seen in FIG. 1, a spacer element 25 is mounted in each of openings 15 :and 17.

The mounting strap 13 is secured to resistor 10 by simply rotating each of the spacer elements 25 in their respective openings so that shoulder portion 29 is rotated from its position shown in broken lines in FIG. 1 to the position shown in full lines in FIG. 1. The rotation of each of the spacer elements 25 .causes the shoulder portions 29 thereon to rotate into engagement with the opposite ends of the resistor body portion 12 to limit the movement of mounting strap 13 with respect to resistor 10. That portion of cylindrical portion 31 (on each of spacer elements 25) which protrudes from mounting strap 13 is then crimped to maintain shoulder portion 29 in engagement with the end of resistor body portion 12 and to maintain spacer element 25 in its opening in mounting strap 13. The resistor would then be operatively secured if desired to a mounting panel or the like by simply inserting suitable bolt members or the like through the bores in each of the spacer elements 25, the bolt members or the like being received by the mounting panel or the like. The tightening of the bolt members or the like would additionally prevent rotation of spacer elements 25 to rigidly maintain the spacer elements 25 in the position shown in FIG. 1. It can be appreciated that spacer elements 25 would maintain resistor 10 in a spaced relationship to the mounting panel or the like or with respect to another resistor stacked therewith (FIG. 12).

With respect to FIGS. 6 and 7, the numeral 10' generally designates a conventional resistor having a mounting strap 35 slidably extending therethrough as in resistor 10. Mounting strap 35 is provided with an elongated slot 67 formed therein which slidably receives a spacer element 39. Spacer element 39 is comprised of a hollow cylindrical portion 41 having a reduced diameter portion 43 adjacent one end thereof. Reduced diameter portion 43 is adapted to be received by slot 37 as illustrated in FIG. 7. Mounting strap 35 is secured to resistor 10' by inserting reduced diameter portion 43 through slot 37 and sliding spacer element 39 in slot 37 until spacer element 39 engages the end of the resistor 10'. That portion of reduced diameter portion 43 which protrudes from mounting strap 65 is then crimped to maintain spacer element 39 in engagement with the end of the resistor 10'. A suitable bolt member or the like may then be extended through bore 45 in spacer element 39, the bolt member being secured to a mounting panel or the like. The tightening of the bolt member or the like assists in maintaining spacer element in engagement with resistor '10 due to the fact that the crimped portion thereof and the upper end of cylindrical portion 41 will be slightly drawn towards each other upon the tightening .of the bolt member or the like. While only one end of the resistor 10 has been shown in FIGS. 6 and 7, it should be understood that the other end of resistor 10 is identical to that which is shown and that a spacer element 39 would be operatively mounted in the other end of mounting strap 35 in an abutting relationshi with the other end :of resistor 10' :as previously described.

With respect to FIGS. 8 and 9, the numeral 10 generally designates a conventional resistor as in FIG. 1 having a mounting strap 47 slid-ably received thereby. Mounting strap 47 is provided with an opening 49 formed therein as seen in FIG. 9. The numeral 51 generally designates a spacer element comprised of a cylindrical portion 53 and a reduced diameterportion 55 at one end thereof thereby defining a shoulder 57 therebetween. Reduced diameter portion 55 of spacer element 51 is adapted to be received in opening 49 in mounting strap 47 as best illustrated in FIG. 9. As seen in FIG. 9, an eccentrically drilled washer element 59 is rotatably mounted on reduced diameter portion 55 between mounting strap 47 and shoulder 57. Mounting strap 47 is secured to resistor 10" by simply rotating the eccentrically drilled washer element 59 on reduced diameter portion 55 so that washer element '59 engages the end of resistor 10" as illustrated in FIGS. 8 and 9. That portion of reduced diameter portion '55 which protrudes from mounting strap 47 is then crimped to maintain washer element 59 in engagement with the end of the resistor 10". A spacer element 51 would also be secured on the other end of mounting strap 47 as just described. Resistor 10" would then be secured to a mounting panel or the like by simply extending bolt members or the like through 4 bore 61 in spacer element 51, the bolt members or the like being secured to a mounting panel or the like. The tightening of the 'bolt members additionally aids in maintaining the eccentrically drilled washer element 59 in that position of its rotative movement as seen in FIG. 9 to positively prevent any movement of resistor 10" with respect to mounting strap 47.

With respect to FIGS. 10 and 11, the numeral 10 designates a conventional resistor such as illustrated in FIG. 1. Resistor 10" is provided with a mounting strap 63 slidably extending therethrough. Mounting strap 63 is provided with an opening 65 formed therein adjacent .one end thereof. The numeral 67 generally designates a spacer element 67 having a reduced diameter portion 69 and an eccentric shoulder portion 71 formed thereon below reduced diameter portion 69. A concentrically drilled washer element 73 embraces spacer element 67 at its eccentric shoulder portion 71 as illustrated in FIG. 11. Reduced diameter portion 69 of spacer element 67 is adapted to be received by opening 65 :as seen in FIG. 11. Mounting strap 63 is secured to resistor 10" by simply rotating spacer element 67 so that eccentric shoulder portion 71 rotates washer element into engagement with the end of resistor 10" as illustrated in FIGS. 10 and 11. That portion of reduced diameter portion 69 which protrudes from mounting strap 63 is then crimped to maintain washer element 73 in engagement with the end of the resistor 10". The other end of mounting strap 63 would also be provided with a spacer element 67. Resistor 10" would then be secured to a mounting panel or the like by extending bolt members or the like through bore 75 in spacer element 67 to effect the rigid connection therebetween and to additionally aid in preventing rotation of spacer element 67 with respect to mounting strap 63.

In each of the embodiments of this invention, the spacer elements would normally be secured to the mountin strap after the mounting strap has been extended through the resistor. However, if so desired, one of the spacer elements could be secured to the mountin strap prior to the insertion of the mounting strap through the resistor and then the second spacer element could be secured to the other end of the mounting strap. In the embodiments of FIGS. 1-5, 8-9 and 10-11, the spacer element is rotated with respect to the mounting strap to cause a cam means to move into engagement with the opposite ends of the resistor to positively prevent any movement of the mounting strap with respect to the resistor. As previously stated, the spacer elements are maintained in engagement with the opposite ends of the resistor by means of crimping and by the bolt members or the like extending therethrough. The vibration resistance qualitics of the embodiments of FIGS. 1-5, 89, and 10-11 are excellent since the stress of vibration must be transferred from a horizontal path to a circuit path (horizontal path being parallel to the longitudinal axis of the resistor and the mounting strap; the circular path being the path which the eccentric spacer must be rotated to move it out of engagement with the end of the resistor). The transfer of the stress of vibration from a horizontal to a circular path is extremely ineflicient which aids in the vibration resistance qualities of the assembly.

The embodiment of FIGS. 6 and 7 likewise positively prevents any movement between resistor 10' and the mounting strap 35 due to the engagement of the spacer elements with the opposite ends of the resistor.

In each of the embodiments of this invention, a rigid connection is provided between the mounting strap and the resistor without reducing the heat dissipation qualities thereof. The means for securing the mounting strap to the resistor as disclosed herein prevents equipment failure due to vibration thereof.

The spacer element embodiment of FIGS. 1-5 is shown to be especially well adapted for use in environ-ments wherein a plurality of resistors are stacked .as seen in FIG. 12. These resistors would be maintained in their stacked position by means of a mounting bolt or the like extendin through the bores 33 of each of the spacer elements 25. The structure of spacer element permits resistors of different lengths to be stacked while maintaining the alignment of the respective bores 33 of the spacer elements which must be accomplished to permit the insertion or extension of a mounting bolt or the like therethrough. Additionally, resistors are manufactured with small tolerances permitted in the length thereof. Assuming that the upper resistor in FIG. 12 is on the plus side of the permitted length tolerance and assuming that the lower resistor in FIG. 12 is on the minus side of the permitted length tolerance, it can be appreciated that the lower spacer element 25 must be rotated more than the upper spacer element 25 to cause the shoulder portions 29 thereon to engage their respective resistors. This also means that a lowermost spacer element 25 will have its cylindrical portion 27 offset inwardly with respect to the axis of bore 33 while the cylindrical portion 27 on the upper spacer element 25 will be offset outwardly with respect to the axis of bore 33 therein. Shoulder portion 29 always maintains the end of the resistor in a spaced relationship with respect to cylindrical portion 27 regardless of the position of rotation of spacer element 25. Thus it can be seen that shoulder portion 29 on the upper resistor prevents contact between the end of the upper resistor and cylindrical portion 27 on the lowermost spacer element 25. Such contact, if permitted, would prevent the alignment of bores 33 and the two spacer elements thereby preventing their stacking due to the fact that a mounting bolt or the like could not be extended through the two bores 33.

The most desirable means of securing the various spacer elements to the mounting strap is to crimp the spacer elements after the spacer elements have been moved into engagement with the resistor. However, the spacer elements can be crimped prior to their being moved into engagement with the resistor but this method of connection is not the preferred method.

Thus it can be seen that the means described herein accomplishes at least all of its stated objectives.

Some changes may be made in the construction and arrangement of my means for securing a mounting strap to a resistor without departing from the real spirit and purpose of my invention, and it is my intention to cover by my claims, any modified forms of structure or use of mechanical equivalents which may be reasonably included within their scope.

I claim:

1. In combination:

a resistor including a body portion having opposite ends, said resistor body portion having a bore formed therein extending therethrough between the opposite ends thereof,

a mounting strap extending through said bore and having opposite ends protruding from the opposite ends of said resistor body portion,

mounting means on said mounting strap adjacent each of its opposite ends,

at least one of said mounting means being movable towards the end of said resistor body portion adjacent thereto and adapted to engage said resistor body portion to limit the movement of said resistor body portion with respect to said mounting strap,

and means securing said mounting means to said mounting strap.

2. The combination of claim 1 wherein at least one of the exposed ends of said mounting strap is provided With an elongated slot formed therein, one of said mounting means being slidably movable in said slot to permit said one mounting means to be moved into engagement with said resistor body portion.

3. The combination of claim 2 wherein at least one of said mounting means is comprised of a hollow cylinder having a reduced diameter portion extending through said slot, said mounting means being secured to said mounting strap by said reduced diameter portion being crimped.

4. The combination of claim 1 wherein at least one of said mounting means is comprised of a hollow cylinder operatively secured to said mounting strap at one end thereof, said hollow cylinder having an eccentric washer means rotatably mounted thereon, said eccentric washer means being rotatably movable on said hollow cylinder to permit said eccentric washer means to be rotated into engagement with said resistor body portion.

5. The combination of claim 1 wherein at least one of said mounting means is comprised of a hollow cylinder operatively rotatably secured to said mounting strap at one end thereof, said cylinder having an eccentric shoulder means formed therein, said cylinder being rotatably movable with respect to said mounting strap to cause sa d eccentric shoulder means to operatively engage one end of said resistor body portion.

6. The combination of claim 5 wherein a concentrically drilled washer means operatively embraces said eccentric shoulder means, said washer means engaging said one end of said resistor body portion.

7. The combination of claim 1 wherein at least one of said mounting means is comprised of first and second cylinder portions having a shoulder portion therebetween and extending therefrom, said second cylinder portion having a smaller diameter than said first cylinder portion, the central axis of said second cylinder portion being offset with respect to the central axis of said first cylinder portion, said mounting means having a bore formed therein extending therethrough, the axis of said bore and the axis of said second cylinder portion being in the same plane, said second cylinder portion adapted to be received by an opening in said mounting strap, said shoulder portion adapted to engage said resistor body portion when said mounting means is rotated with respect to said mounting strap.

8. The means of claim 1 wherein at least one of said mounting means is comprised of an eccentrically drilled cylinder operatively rotatably mounted on said mounting strap at one end thereof, said cylinder having shoulder means extending therefrom, said cylinder being rotatably moveable with respect to said mounting strap to cause said shoulder means to operative engage one end of said resistor body portion.

9. The combination of claim 8 wherein a plurality of resistors having mounting straps secured thereto are operatively secured to a supporting means in a stacked r lationship, said shoulder means extending outwardly from said cylinder on each of said mounting means to maintain the resistor associated therewith in a spaced relationship with respect to said cylinder to prevent the contact of the cylinder of one mounting means on one resistor with another resistor in the stacked assembly to permit the bores formed in the eccentrically drilled cylinders to be aligned.

10. The means of claim 1 wherein at least one of the ends of said mounting strap is provided with an elongated slot formed therein, one of said mounting means being slidably movable in said slot to permit said one mounting means to be moved into engagement with said resistor body portion.

11. The means of claim 1 wherein at least one of said mounting means is comprised of an eccentrically drilled cylinder operatively rotatably mounted on said mounting strap 'at one end thereof, said cylinder having a shoulder means extending therefrom, said cylinder being rotatably movable with respect to said mounting strap to cause said shoulder means to operatively engage one end of said resistor body portion, said cylinder being crimped onto said mountin strap to maintain said cylinder on said mounting strap and to maintain said shoulder means in engagement with said one end of said resistor body portion.

12. The means of claim 1 wherein at least one of the ends of said mounting strap is provided with an elongated slot formed therein, one of said mounting means being slidably movable in said slot to permit said one mounting means to be moved into engagement with said resistor body portion, said mounting means being crimped to maintain said mounting means in said slot and to maintain said mounting means in engagement with said resistor body portion.

13. In combination:

an electrical device including a body portion having opposite ends, said electrical device body portion havin a bore formed therein extending therethrough between the oposite ends thereof,

a mounting element extending through said bore and having opposite ends protruding from the opposite ends of said electrical device body portion,

mounting means on said mounting element adjacent each of its opposite ends,

:at least one of said mounting means being movable towards the end of said electrical device body pormounting means are operatively secured to said device in a substantially opposing relationship.

References Cited UNITED STATES PATENTS 2,326,469 8/1943 Leichner 248-309 FOREIGN PATENTS 120,775 12/ 1945 Australia.

DARRELL L. CLAY, Primary Examiner.

E. GOLDBERG, Assistant Examiner. 

